CN1285067C - Flat panel display based on carbon nanotubes and manufacturing method thereof - Google Patents

Abstract

A method for manufacturing a flat panel display based on carbon nanotubes, the method at least includes the following steps: corroding row conductive strips on the conductive layer of the back panel; plasma deglue; corroding the column conductive strips on the conductive layer of the back panel; Carbon nanotubes are grown on the layer as a cathode emitter; a phosphor layer is made on the transparent conductive layer of the front panel; the functional surfaces of the back panel and the front panel are combined and assembled. The production of carbon nanotubes is to prepare carbon nanotubes by DC arc discharge in quartz tubes; centrifugal purification, ball mill splitting; directional transplantation of carbon nanotubes to conductors, and the directional growth of carbon nanotubes as cathodes; transparent conductive surfaces on the front panel A phosphor layer is made on the layer; it is printed by screen printing method. A spacer is made between the back panel and the front panel for support, and the back panel and the front panel keep a certain distance from each other. The invention adopts the vacuum microelectronic technology and utilizes the carbon nanotube field cooling emission principle to produce a high-efficiency and long-life field emission flat-panel display, which has low cost, high resolution and bright colors.

Description

Flat panel display based on carbon nanotubes and manufacturing method thereof

technical field

The invention relates to a flat panel display and a manufacturing method thereof, in particular to a manufacturing method and device based on a carbon nanotube flat cathode emission display.

Background technique

At present, the display technology has developed from the common hot cathode ray tube (CRT), liquid crystal display (LCD) and plasma flat panel display device (PDP) in the past to matrix addressing, high resolution Field emission flat panel display device (FED) with high efficiency and long life, which has great advantages compared with hot cathode ray tube (CRT), liquid crystal display (LCD) and plasma flat panel display device (PDP) , specifically manifested in the advantages of low working voltage, low production cost, low energy consumption, thinner, higher brightness and definition. CRT monitors are bright in color, but low in definition, high in energy consumption and bulky, and are products that will be replaced in more places; LCD monitors are high in definition and thin in thickness, but do not emit light themselves, require external light sources, and have dim colors. .

In recent years, more and more experts have begun to try to use various technologies to manufacture ultra-thin displays. However, due to various reasons, most of the existing experimental products have shortcomings such as poor clarity and small area, and the maturity of the technology has not been improved. Good breakthrough.

Contents of the invention

The object of the present invention is to provide a flat-panel cathode-emitting display based on carbon nanotubes and a manufacturing method thereof, which has low display cost, high definition, bright colors, long service life, large fluorescent area, and meets environmental protection requirements.

The purpose of the present invention is achieved like this:

A carbon nanotube flat-panel display, which includes a back panel, a fluorescent light-emitting layer and a front panel, wherein the front panel and the back panel are combined to form a display, and the fluorescent light-emitting layer is arranged between the front panel and the back panel, and the back panel Row electrodes and column electrodes of carbon nanotubes are arranged on the inner surface layer, the row electrodes are cathodes, the column electrodes are grid electrodes, the row electrodes and column electrodes are provided with electrode leads, and the inner surface layer of the front panel is provided with transparent conductive electrodes and The phosphor powder of three primary colors, the carbon nanotubes of row electrodes and column electrodes on the inner surface layer of the back panel, and the phosphor powder of three primary colors on the inner surface layer of the front panel constitute the fluorescent light-emitting layer.

The inner surface layer of the back panel is provided with a spacer with screen printing missing to support the front panel and the back panel. The spacers are arranged between the gaps of the discharged carbon nanotubes, and there is a distance between the spacers. The spacer is divided into a double-layer sandwich structure with upper and lower parts, the lower half is arranged on the row electrode layer, and the upper half is arranged on the column electrode layer. The specific material of the spacer is transparent low-melting glass powder material. According to needs, and in order to ensure the supporting force, the spacer can be made into a multi-layer structure.

The back panel is a glass substrate layer or a ceramic substrate layer, on which a conductive layer is arranged, or a low-resistance conductive film glass is directly used. Carbon nanotubes are made by directional growth on the conductive layer of the back plate.

The front panel and the back panel are combined to form a parallel exhaust pipe at the reserved opening of the side package of the display body, and the opening of the exhaust pipe communicates with the reserved opening. A getter is provided in the exhaust pipe.

A method for manufacturing a flat panel display based on carbon nanotubes, the method at least includes the following steps:

1) corroding the conductive strips on the conductive layer of the back panel;

2) Print silver paste on the row conductive strip by silk screen method;

3) solidifying the silver paste as the lead-out end of the row conductive strip;

4) Make an isolation layer on the row conductive strip of the back panel, and make a second conductive layer on the isolation layer;

5) corroding the conductive strips on the isolated second conductive layer;

6) Print silver paste on the column conductive strips by silk screen method;

7) solidifying the silver paste as the lead-out end of the row bus bar;

8) On the row conductive strips on the conductive layer of the back panel, use electrophoresis method to grow carbon nanotubes oriented as cathode emitters. The specific process is: prepare carbon nanotubes by direct current arc discharge in the quartz tube; centrifugal purification, ball mill splitting; directional transplantation Carbon nanotubes onto row conductive strips;

9) Make a phosphor layer on the transparent conductive layer of the front panel;

10) Apply low-melting point glass powder to the front panel or the back panel to set the sealing material, make a frame, and solidify as a whole; align the front panel and the back panel, install them in the fixture, and seal the front panel and the back panel Reserve an exhaust port around the frame, set the exhaust pipe at the exhaust port, and put it into the furnace for sintering; through the exhaust pipe, vacuumize the inside where the front panel and the back panel are combined.

The step of corroding the conductive strips on the conductive layer of the back panel is to print silver paste as the lead-out end of the conductive layer by silk screen printing; solidify; and use electrophoresis to grow carbon nanotubes in a direction as the cathode. The specific steps of making the carbon nanotubes are: preparing the carbon nanotubes by DC arc discharge in the quartz tube; centrifugal purification, ball milling and splitting; and directionally transplanting the carbon nanotubes onto the conductor.

The step also includes: coating phosphor powder on the conductive layer of the front panel to make a light-emitting layer. Specifically, the fluorescent powder is evenly printed on by screen printing method.

The manufacturing steps of the row conductive strips and the column conductive strips are: coating photosensitive glue, pre-baking the photosensitive glue, exposing to ultraviolet light, developing photoresist, hardening the photoresist film, and corroding the conductive strip.

In order to support the back panel and the front panel and maintain a certain distance from each other, the step also includes making spacers after the functional layer of the row conductive strips on the back panel is completed,

The manufacturing steps of the spacers include: after the conductive strips are made, specifically plasma degumming, mixing dark low-glass powder with photosensitive glue, pre-baking the photosensitive glue, exposing to ultraviolet rays, photolithography and developing, and firing in a furnace.

The step of making the spacer further includes: after the column conductive strips are made, mix the dark low-glass powder with the photosensitive glue, and apply it on the board to make the upper half of the spacer. This step can be omitted for displays with long, narrow shapes and thick glass.

The spacers are printed in multiple layers by silk screen printing as required, so as to meet the requirements of the support height.

The assembly steps are as follows: apply low-melting glass powder on the periphery of the front panel or the back panel, set a sealing material, make a frame, and solidify the whole; align the front panel and the back panel, load them into the fixture, and place Reserve an exhaust port around the frame sealed by the back panel, set the exhaust pipe at the exhaust port, and put it into the furnace for sintering; through the exhaust pipe, vacuumize the inside of the front panel and the back panel.

The above steps also include doping glass particles in the low-melting point glass powder, so as to make the sealing material have a certain support.

The exhaust pipe setting in the above steps includes drilling holes on the side where the exhaust pipe communicates with the reserved exhaust port, and fitting the side of the exhaust pipe with the small hole parallel to the reserved exhaust port, and aligning the small hole with the reserved port. Leave an exhaust port, coat the periphery of the exhaust pipe with low-melting glass powder, and close the end of the exhaust pipe that fits the reserved exhaust port.

The end of the exhaust pipe that fits the reserved exhaust port is thinned, and a small hole is punched in the thinner pipe body. Specifically, laser or ultrasonic waves can be used to drill holes for the exhaust pipe, and there are more than one small holes on a straight line.

In order to save the effective area of the display and enhance the vacuum degree, a getter is installed in the exhaust pipe, and when the exhaust reaches the limit, the port of the exhaust pipe is sealed, and the exhaust pipe with the getter is placed in a high-frequency induction coil for heating To activate, seal off a section of exhaust pipe with getter.

The back panel is low-resistance ITO glass or flat glass or ceramic substrate with a conductive layer

According to the analysis of the above technical solutions, the present invention adopts vacuum microelectronics technology and utilizes the carbon nanotube field cooling emission principle to produce a high-resolution, long-life field emission flat-panel display, which has low cost, high brightness, and bright colors. The specific advantages are as follows:

1. Make a functional layer on ordinary flat glass, and make carbon nanotubes on the functional layer as the cathode, X, Y orthogonal lattice addressing, the cost is low and the definition is high.

2. The exhaust pipe is side-mounted and sintered with the screen as a whole. The overall display is thinner, and the air getter is installed in the exhaust pipe, which not only saves the effective area of the display, but also seals off after high-frequency activation, which can keep the screen for a long time. High vacuum, prolong service life.

3. The spacer in the screen is a double-layer sandwich structure, and the low glass powder is a special shape independent body. The discharge chambers are connected and can resist strong vacuum pressure, so the display area can be made larger.

4. The inner layer of the front panel is coated with low-voltage, high-brightness three-color phosphor powder, so the color of the display is very bright.

Description of drawings

Fig. 1 is a schematic diagram of the overall three-dimensional structure of the present invention;

Fig. 2 is a schematic diagram of the structure of the front and rear panels in the disassembled state of the present invention;

Fig. 3 is a schematic diagram of the planar structure of the lower half of the spacer in the present invention;

Fig. 4 is a schematic diagram of the planar structure of row conductive strips of the present invention;

Fig. 5 is a schematic diagram of the planar structure of the column conductive strips of the present invention;

Fig. 6 is a schematic diagram of the planar structure of the upper half of the spacer in the present invention.

Detailed ways

The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

Referring to Figures 1-6, the present invention is a carbon nanotube flat-panel display, which includes a back panel 1, a fluorescent light-emitting layer and a front panel 2, wherein the front panel 2 and the back panel 1 are combined to form a display body, and the fluorescent light-emitting layer is arranged Between the front panel 2 and the back panel 1. Row electrodes 11 and column electrodes 12 with carbon nanotubes are arranged on the inner surface layer of the back plate 1 . The row electrodes 11 are cathodes, the column electrodes 12 are grids, the row electrodes 11 and the column electrodes 12 are provided with electrode leads, and the inner surface layer of the front panel 2 is provided with a transparent conductive electrode 22 and three primary color phosphors 21. The row electrodes 11 and column electrodes 12 on the surface layer and the three primary color phosphors 21 on the inner surface layer of the front panel 2 constitute a fluorescent light-emitting layer. Specifically, the front panel 2 is a transparent substrate layer, and the back panel 1 is a glass substrate layer or a ceramic substrate layer, on which a conductive layer is provided, or a low-resistance conductive film glass is directly used. The carbon nanotubes are made by directional growth along the row conductive strips on the back panel 1 .

The front panel 2 and the back panel 1 are combined to form a parallel exhaust pipe 3 at the side package reserved opening of the fluorescent light source body. The volume of the tube 3 results in a thickening of the body of the fluorescent light source. The exhaust pipe 3 is provided with a getter 4, which can not only increase the effective area of the fluorescent light source body, but also further meet the vacuum requirement of the fluorescent light source body by using the getter, and improve the service life of the fluorescent light source body.

In order to ensure that, for a large-area fluorescent light source body, there can be a certain pressure bearing capacity between the front panel 2 and the back panel 1, and the inner surface of the back panel 1 is provided with a support for the front panel 2 and the back panel. 1 role of the isolator 13,14. The spacer is a double-layer sandwich structure divided into upper and lower parts, the lower half 13 is arranged on the row electrode 11 layer, and the upper half 14 is arranged on the column electrode 12 layer.

Spacers 13 and 14 are made of transparent low-melting glass powder. The specific shape of the spacers 13, 14 conforms to the gaps of the discharged carbon nanotubes, so they are arranged between the gaps of the discharged carbon nanotubes, and the spacers 13, 14 have a distance from each other. In order to ensure the accuracy, the spacers 13 and 14 are made by screen printing, and the spacers 13 and 14 are required to be multi-layered according to different thicknesses.

In order to stabilize the overall uniform distance between the front panel 2 and the back panel 1 during vacuuming, glass beads are provided in the material 5 encapsulated around the sides of the front panel 2 and the back panel 1 to form the body of the fluorescent light source, so that It overcomes the shortcoming that the sealing material causes the overall uniform distance between the front panel and the back panel to be inconsistent, and ensures the consistency of the pressure.

The manufacturing method of the invention includes manufacturing other components such as the back panel 1 , the front panel 2 , and the exhaust pipe 3 . The specific production method is:

Production of back panel 1:

Cut low-resistance ITO glass (or flat glass, ceramic substrate) to appropriate size, clean and remove oil and debris, print silver paste as the lead-out end by screen printing, and cure. Directly grow carbon nanotubes 12 as cathodes by electrophoresis, screen printing or thermal decomposition.

Specific steps include:

1. Cut low-resistance IT0 flat glass (or flat glass for conductive layer, ceramic substrate) into appropriate size, clean and remove oil and debris. Glass cleaning, including: rinsing with tap water, rinsing with deionized water, ultrasonication with acetone, ultrasonication with absolute ethanol, ultrasonication with deionized water, rinsing with hot and cold deionized water, and dehydration with absolute ethanol.

2. Make row conductive strips: apply photosensitive adhesive, pre-baking photosensitive adhesive, ultraviolet exposure, photoresist development, photoresist hardening, etch conductive strips on the conductive layer, and use silk screen printing method to print silver paste as the terminal;

3. Making the lower part of the spacer: Plasma degumming, mixing dark low-glass powder with photosensitive glue and coating it on the row electrode layer, pre-baking the photosensitive glue, exposing to ultraviolet light, photolithography and developing, and sintering in the furnace. If the height is not enough, repeat the above steps.

4. Make column conductive strips: apply photosensitive adhesive on the second conductive layer, bake the photosensitive adhesive before, expose to ultraviolet light, develop photoresist, harden the photoresist film, corrode the column conductive strip on the second conductive layer, and print with silk screen method The upper silver paste is used as the lead-out end;

5. Making the upper part of the spacer: Plasma degumming, mixing dark low-glass powder with photosensitive glue and coating it on the column electrode layer, pre-baking the photosensitive glue, exposing to ultraviolet light, photolithography and developing, and sintering in the furnace. If the height is not enough, repeat the above steps. This step can be omitted for displays with long, narrow shapes and thick glass.

6. Directly grow carbon nanotubes on the cathode conductive strips as cathode emitters by electrophoresis. The specific method of transplanting carbon nanotubes: carbon nanotubes are prepared by direct current arc discharge in a quartz tube, then purified by centrifugation, split by ball milling, and then directional transplanted carbon nanotubes onto conductors as cathodes by electrophoresis.

Front panel 2 production:

Clean oil stains and glass slag, mix green powder and photosensitive glue and apply it on the board, pre-baked the photosensitive glue, exposed to ultraviolet light, developed photoresist, hardened the photoresist film, and applied ammonium dichromate as an aging layer; In the same steps, apply red and blue primary colors on the board respectively, and apply low glass powder on the board as a peripheral sealing material; dope glass particles in the low melting point glass powder so that the sealing material has a certain support; enter the furnace to solidify .

Assembly:

Align the front panel 2 and the back panel 1 with the low-glass-powder coating sealant around them, and install them in the jig. Install exhaust pipe 3 again, coat low glass powder. Enter the furnace for sintering, install the getter 4 in the exhaust pipe 3, and exhaust. When the exhaust reaches the limit, seal it. Activate the getter 4 of the exhaust pipe 3, and seal the excess exhaust pipe 3 with a fire head.

When applying glue, according to the thickness of the photosensitive glue, select the mesh number of the screen film, and apply a layer of photosensitive glue with uniform thickness on the glass plate by silk screen printing. The pre-baking process is aimed at the thicker nickel-chromium conductive layer and longer chemical corrosion time, so the photosensitive adhesive film is thicker, the oven temperature is 85 degrees, and the pre-baking time is 25 minutes is more suitable.

The exposure time can be set to 11-15 seconds, and the specific time can also refer to the specific film thickness, pre-baking time and other parameters; the development is to dissolve the unsensitized photoresist in the developer solution; The glass plate with a good bottom film is placed flat in the aluminum box with holes at the bottom, and the photoresist side is facing up, and then baked; corrosion is the chemical corrosion of the nickel-chromium conductive layer at room temperature; degumming is to clean the etched glass plate Cleaning with deionized water, dehydration, drying, oxygenation and degumming.

Coating low glass powder and fluorescent powder: use the screen printing method to print the mixture of low glass powder and photosensitive adhesive as the spacer in the middle. Of course, the size of the transparent spacer is very small and does not affect the exhaust passage. Phosphor powder is printed by screen printing method. The phosphor powder must be stirred evenly by a mixer during printing. The thickness of the printed phosphor is determined by the mesh number of the screen film.

Coating frame: Mix the low glass powder and apply it on the front panel as a frame. If the frame is not completely closed, the installation opening for the exhaust pipe should be reserved before entering the furnace for curing.

Pulling the exhaust pipe: Thinning one end of the exhaust pipe on the burner, if the exhaust pipe is at right angles, it must be bent after being thinned, and the thin end is sealed, and then laser or ultrasonic is used to punch more than one on the thin pipe holes, they are all in a straight line. Put the sintered upper and lower glass plates and the processed exhaust pipe into the tool, align these small holes with the openings reserved on the frame, coat with low glass powder, put them into the furnace for sintering, and put the exhaust pipe burnt to the edge of the screen.

Getter: Put the getter in the exhaust pipe, which is pressed on the high-purity nickel sheet, keep the exhaust pipe upward, and then connect the vacuum unit to exhaust. Seal it when exhaust reaches the limit, and keep the seal as far away from the getter as possible. Activate the getter and seal the length of the exhaust pipe with the getter with a torch so that no more than about 3 mm of the exhaust pipe remains on the screen.

The above embodiments are only used to illustrate the present invention without limitation, although the present invention has been described in detail with reference to the above preferred embodiments, those of ordinary skill in the art should understand that the present invention can be modified, deformed or equivalently replaced without departing from The spirit and scope of the present invention should be included in the claims of the present invention.

Claims (19)

1. A carbon nanotube flat-panel display, which comprises a back panel, a fluorescent light-emitting layer and a front panel, wherein the front panel and the back panel are combined to form a display, and the fluorescent light-emitting layer is arranged between the front panel and the back panel, and is characterized in that : the inner surface layer of the back panel is provided with row electrodes and column electrodes of carbon nanotubes, the row electrodes are cathodes, the column electrodes are grid electrodes, the row electrodes and the column electrodes are provided with electrode leads, and the inner surface layer of the front panel There are transparent conductive electrodes and three-primary-color phosphors, and the row electrodes and column electrodes of carbon nanotubes on the inner surface of the back panel and the three-primary-color phosphors on the inner surface of the front panel form a fluorescent light-emitting layer; The front panel and the back panel are combined to form a parallel exhaust pipe at the reserved opening of the side package of the display body, and the opening of the exhaust pipe communicates with the reserved opening. 2. The carbon nanotube flat-panel display according to claim 1, characterized in that: the inner surface of the back panel is provided with a spacer for keeping the distance between the front panel and the back panel by screen printing. 3. The carbon nanotube flat-panel display according to claim 2, wherein the spacers are arranged between the gaps of the discharged carbon nanotubes, and there is a distance between the spacers. 4. The carbon nanotube flat-panel display according to claim 2, characterized in that the spacers are divided into upper and lower parts of a double-layer sandwich structure, the lower half is arranged on the row electrode layer, and the upper half is arranged on the column electrode layer. 5. The carbon nanotube flat-panel display according to claim 2, 3 or 4, wherein the spacers are made of transparent low-melting glass powder. 6. The carbon nanotube flat-panel display according to claim 1, characterized in that: the back plate is a glass substrate layer or a ceramic substrate layer, on which a conductive layer is arranged. 7. The carbon nanotube flat-panel display according to claim 1, wherein the back panel is made of low-resistance conductive film glass. 8. The carbon nanotube flat-panel display according to claim 1, wherein a getter is provided in the exhaust pipe. 9. A method for manufacturing a flat panel display based on carbon nanotubes, characterized in that: the method at least includes the following steps: 1) corroding the conductive strips on the conductive layer of the back panel; 2) Print silver paste on the row conductive strip by silk screen method; 3) solidifying the silver paste as the lead-out end of the row conductive strip; 4) Make an isolation layer on the row conductive strip of the back panel, and make a second conductive layer on the isolation layer; 5) corroding the conductive strips on the isolated second conductive layer; 6) Print silver paste on the column conductive strips by silk screen method; 7) solidifying the silver paste as the lead-out end of the row bus bar; 8) On the row conductive strips on the conductive layer of the back panel, use electrophoresis method to grow carbon nanotubes oriented as cathode emitters. The specific process is: prepare carbon nanotubes by direct current arc discharge in the quartz tube; centrifugal purification, ball mill splitting; directional transplantation carbon nanotubes onto row conductive strips; 9) Make a phosphor layer on the transparent conductive layer of the front panel; 10) Apply low-melting point glass powder to the front panel or the back panel to set the sealing material, make a frame, and solidify as a whole; align the front panel and the back panel, install them in the fixture, and seal the front panel and the back panel Reserve an exhaust port around the frame, set the exhaust pipe at the exhaust port, and put it into the furnace for sintering; through the exhaust pipe, vacuumize the inside where the front panel and the back panel are combined. 10. The method for manufacturing a flat panel display based on carbon nanotubes according to claim 9, characterized in that: said step 9) specifically comprises: coating the conductive layer of the front panel with phosphor powder. 11. The manufacturing method based on carbon nanotube flat panel display as claimed in claim 10, characterized in that: said step of coating phosphor powder on the conductive layer of the front panel is to apply phosphor powder to three The base color is printed evenly. 12. The manufacturing method based on carbon nanotube flat panel display as claimed in claim 9, characterized in that: the manufacturing steps of the row conductive strips and the column conductive strips are: coating photosensitive glue, pre-baking the photosensitive glue, exposing to ultraviolet rays, light The resist is developed, the photoresist hardens the film, and the conductive strips are corroded. 13. The method for manufacturing a flat-panel display based on carbon nanotubes as claimed in claim 9, characterized in that: said spacer manufacturing step further comprises: after the column conductive strips are manufactured, dark low glass powder and photosensitive adhesive Mixed and coated on the column electrode layer to make the top half of the spacer. 14. The method for manufacturing flat-panel displays based on carbon nanotubes according to claim 13, characterized in that: the manufacturing process of the upper half of the spacer is to adopt the method of screen printing on the column electrode layer as required Print in multiple layers. 15. The manufacturing method based on carbon nanotube flat panel display as claimed in claim 9, characterized in that: setting the exhaust pipe in the above step includes punching holes on the side of the exhaust pipe, and placing the side of the exhaust pipe with small holes Fit the reserved exhaust port in parallel, the small hole is aligned with the reserved exhaust port, the periphery of the exhaust pipe is coated with low-melting glass powder, and the end of the exhaust pipe attached to the reserved exhaust port is closed. 16. The manufacturing method based on carbon nanotube flat panel display according to claim 15, characterized in that: the end of the exhaust pipe attached to the reserved exhaust port is thinned, and small holes are drilled on the thinner pipe body. 17. The method for manufacturing a flat panel display based on carbon nanotubes according to claim 15 or 16, characterized in that the exhaust pipe is drilled by laser or ultrasonic waves. 18. The method for manufacturing a flat panel display based on carbon nanotubes according to claim 17, characterized in that there are one or more small holes, and more than one small hole is on a straight line. 19. The manufacturing method based on carbon nanotube flat panel display as claimed in claim 9, characterized in that: a getter is installed in the exhaust pipe, and when the exhaust reaches the limit, the port of the exhaust pipe is sealed, and the getter is installed. The exhaust pipe of the getter is placed in the high-frequency induction coil for heating and activation, and a section of the exhaust pipe with the getter is sealed.

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